Grinding machine



y 1930. w. H. VCHAPMAN 1,758,649

GRINDING MACHINE Filed Jan. 10, 1927 3 Sheets-Sheet 1 2o 40 24 l 1 38 ll 1 May 13, 1930. w. H. CHAPMAN GRINDING MACHINE Filed Jan. 10, 1927 3Sheets-Sheet 2 llilrmltill ll /N\/ENTOQ- WILL/AM H. CHAPMAN,

HIS ATTOQNEV.

May 13, 1930. w. H. CHAPMAN GRINDING MACHINE Filed Jan. 10, 1927 3Sheets-Sheet 5 Patented May 13, 1939 NE'IE STAT T :0 F FI CE \VILLIAM-I-I. CHAPMAN, 0F IMQN'J'.CLAIR, NEW JERSEY, ASSIGNO'R TO GENERAL MOTORSCORPORATION, OF ZDETROIT, "MICHIGAN, A CORPORATION OF DELAWARE GRINDINGBEACH-ENE Application filed January 10, 1927. Serial No. 1G0,068.'

placed in a V-block and rotated under an indicator so that contact is atpoints 120:apart,

three high spots will be noted. There is r no satisfactory theory toaccount for this. Possibly initial irregularities in the workengage withthe guide or the wheels in a manner to deflect the work from a normalcentral position, thus resulting in slip and the grinding of flats whichremain equally Spaced. Grinding of the work above or below a normalposition in the grinding throat between the wheels introduces conditionshard to control or correct for and results in inaccurate sizing.

An object of the inventionis to provide, for centerless grinders, animproved form of work guide which will insure the production ofperfectly round work andavoid the above and other defects of priormachines. Another object is 'to provide improved mechanism for locatingand holding work-pieces in a definite and established axis or path oftravel between the wheels to the end that accurate sizing of the work ispromoted.

To these ends and also to improve generally upon devices of thecharacter indicated the invention consists in the various matter'shereinafter described and claimed.

The invention, in its broader aspects, is not necessarily limited totlieiparticular embodiment selected for illustration in theIancompan-ying drawings in which Figure 1 is a'plan view and Figure 2 isa front elevation of portions of a .centerless grinder with a centeringandlocating device inoperative position.

. Figure 3 is aside elevation partly in .section of the work guidesandassoeiated medl i A nu anism.

of which is adjustable endwise.

Figures land 5 are detail sectional views f the work guides.

Figures 6 and 7 are perspective views of certain work guides.

F igures S, 9, 10, and 11 are diagrammatic views indicating the relationof the work and its guides to the wheels, Figure 11 being amodification.

The numeral 6 indicates a grinding w h'eel rotatable at high-speedwithits shaft 8, and 10 indic'a'tesa slower regulating wheel whose axisor shaft 12 is tiltable in-a plane parallel to a work :guide extendingbetween the wheels. The grinding wheel moves downwardly at the work, theregulating wheel moves upwardly at the work, and the work guide isadjustable to locate and support 'work-pieces for lravel through themachine with the axes of the work-pieces always in a b definite.locatiompreferably at'the point of nearest approach of the wheels. Anysuitably known form of control mechanism :may be provided to cause thewheels to feed towards or from one another and the interposed work. Thewheel shafts and their mountings are arranged to extend away from eachother and from the wheels on the opposite sides of the guide toneutralize the tendency for deflection :of the shafts during grinding tothus maintain the acting parts of the wheel 0 tering device is provided.This comprises a centering rod 16 haviiigrend openings to be engaged byaligned xtape'r centers 18 one The taper centers 1:8 are carried "byswingable arms 20,

reachpivoted at 225011 a-standard 24 andeach "having at one end a screw26 arranged to engage either in a tapped opening 28 in .an opposite,companion standardmrin ia tapped opening 3.0 inthe same (standard.Figure 1 shows rod in cente i g position with, a

' operated at a common source.

dummy or reference work-piece D sleeved upon it, the piece beingpreviously accurately sized externally and accurately fitting the rodinternally for the purpose of locating, with reference to it, the workguides and the wheels for producing finished work of the same externalsize. This reference axis is preferably arranged to pass through thegrinding throat at the point of nearest approach of the wheels. By theuse of difierent sized dummy work pieces, all sizes of work can beground by the wheels at the same level so no inaccuracies will resultfrom a variation in the sizing recess between the wheels. After locatingthe wheels and work guide by moving them into contact with the referencework-piece, the centering rod is removed and its supporting arms swungto vertical inoperative position.

The machine has a lower supporting bar or guide'32 and a parallel uppersupporting bar or guide 34, each bar being secured at its ends to aslide block 36. Each block is grooved to slide vertically in thestandards 24 and its ends are split as at 38 to enable it to be clampedin adjusted positions on the standards by bolts 40. The blocks and barsare simultaneously movable towards or from each other in equal degreebygearing Swivelled to the lower blocks are screws 42 freely guidedthrough openings in the bases of the standards but supported and fedendwise by worm wheels 44 connected for simultaneous rota- 1 tion by ashaft 46. The upper slide blocks are suspended by rotatable screws 48guided loosely through cross bars 50 connecting the standards, thescrews being supported and fed endwise by worm wheels52 which areconnected for simultaneous rotation by a shaft 54. The worm wheels 44and 52 at the front are driven by worms 56 and 58, respectively, and theworm shafts are connected by sprocket wheels 60 and a chain 62,

.1 the upper worm shaft being directly controlled by a hand wheel 64.Thus the guide bars move together but in opposite directions equally sothat work-pieces of different diameters will be supported at the samelevel be- ."ftween the wheels. Individual movement, as

to provide for initial adjustment or for wear, is eifccted by lining tothe screws. hand wheels 66 which enable either screw to be turnedindividually to feed it endwise past its worm t wheel.

-' grinding. wheel and projects beyond it to.-

wards the front or work receiving side as shown in Figures 1 and 10 sothat by pressing the work towards this projecting portion of theregulating wheel, the work is started rotating before it reaches thegrinding wheel and hence the grinding of flats or the mutilation of theleading end of the Work by the grinding wheel is obviated. The work maybe pressed towards the regulating wheel and the lower work guide by anysuitable mech anism. As shown, a blade 74 having a bevelled end 76 isslidably mounted in a recess 78 of the upper guide bar and is pressedclownwardly by a leaf spring 80 between. the top edge of the blade andthe top wall of the recess. The blade is loosely confined laterally by acover plate 82 clamped by screw bolts 84 against a shoulder or ledge 86surrounding the blade recess, some of the bolt heads having flats sothat the cover plate and blade can be removed upon a partial turn of thebolts. The downward movement of the blade under influence of the springis limited by nuts 88 on adjustable stop screws 90 threaded in the bladeand passing loosely through openings in the top of the bar.

The lower work guide which forms one of the important features of theinvention comprises a plurality of blades the work engaging points ofwhich are arranged in an are having a radius R exactly equal to theradius of a finished and accurately sized work-piece, the blades beinglocated wholly to one side of the axis A or path of travel of the centerof the work-pieces. In a recess near the center of the length of the bar32, at a location including the peripheral width of the wheels, a blade94 is secured by bolts passed through openings 96. The blade is let intoa recess 98 of the bar and is adjustable edgewise by a screw 100 tolocate its top edge 102 just beyond the top of bar 34 or flush with awear plate 104 on the bar. The blade is located wholly at one side ofthe center of the bar and on the side opposite the regulating wheel.Other blades 106, 108, are spaced apartin parallel relation to oneanother and to the blade 94. Blades 106, 108, and 110 are adjustablymounted in grooves of end guide blocks 112 and 114 which are rigidlyspaced by a back plate 116 secured to them by screws 118. The guideblock 112 is secured to bar 32 by a bolt 120 passing through the block112, through a spacing member or bushing 122 which is in a notch ofblade 94, and

through the bar 32. The spacing member 122 holds the end block 112 flushwith the side of the bar 32. The guide block 114 is secured directly tothe side of the bar 32 by a bolt 124. The blades 106, 108 and 110 haveend faces 126, 128 and 130 which are inclined and these faces may bestraight or transversely curved. The blades are adjustable edgewise byadjusting screws 132, 134 and 136 engaging the bottom edges of theblades and threaded in bottom plates 138 attached to the end guideblocks by screws 1 10. Clamping screws 144, 146 and 148, threaded in theguide blocks, hold the blades in adjusted positions in their grooves.

Vhen a dummy or accurately sized reference work-piece D has been locatedby the centering device in the manner described, the upper and the lowerbars and the wheels (then idle) are moved to work contacting position.The blades are adjusted so that they contact with different portions ofthe circumference of the dummy or reference work-piece, their end facesor work engaging portions 126, 128 and 130 being located in an arc of aradius R exactly equal to that of the reference workpiece. Once theblades and the regulating wheel are thus located, they are allowed toremain and, during grinding of the real work-pieces V, only the grindingwheel is fed in towards the work as the work reaches size. Meanwhile,the upper springpressed blade 74 keeps the work pressed towards theregulating wheel and the work blades. The blades being located at oneside of the axis of the work, the downward pressure that the grindingwheel produces is largely exerted or transferred laterally to theregulating wheel which insures uniform rotation without the slip thatmay occur if the pressure is wholly or largely exerted against a worksupport that is continued over under the regulating wheel side of thework path. The rough work is so guided that the cutting action trues upany out of round condition and as it reaches size, it is supported inthe proper final position at a number of accurately located contactpoints on its periphery and a true cylinder results.

If desired, the work guide may be a single wide blade 150 having aradius equal to that of an accurately sized and finished work'- piece asindicated in Figure 11. This guide also presents a plurality of workcontacting portions in the finished arc and irregularities that exist inthe rough work do not perpetuate themselves as they do when striking ata single point of support. The sectional type of support, however,allows grit to work out readily and is conducive to a smooth finish.

I claim:

1. In a centerless grinding machine, in combination, a grinding wheelrotatable at relatively high speed, a regulating wheel rotatable atrelatively low speed, the grinding wheel moving downwardly and theregulating wheel moving upwardly with respect to an interposedwork-piece, and a work guide having work engaging portions located in anarc of a radius equal to that of a finished and accurately sizedwork-piece, said work guide being located wholly at the side of the axisof the work-piece opposite the regulating wheel whereby the work is heldfrom lateral displacement by a plurality of contacts with the guidewithout loss of rolling contact with the regulating wheel; substantiallyas described.

2. In a centerless grinding machine, in combination, a grinding wheelrotatable at relatively high speed, a regulating wheel rotatable atrelatively low speed, the grinding wheel moving downwardly and theregulating wheel moving upwardly with respect to an interposedwork-piece, a work guide having a plurality of work engaging portionslocated in an arc of the same radius of curvature as a finished andaccurately sized workpiece and arranged to support the work-piece at theside of its axis opposite the regulating wheel, and a member forpressing the workpiece towards the work guide and towards the regulatingwheel; substantially as described.

3. In a centerless grinding machine, in combination, a grinding wheelrotatable at relatively high speed, a regulating wheel rotatable atrelatively low speed, the grinding wheel moving downwardly and theregulating wheel moving upwardly with respect to an interposedwork-piece, and a guide for the work-piece comprising spaced bladeshaving their end portions positioned to conform to the periphery of afinished and accurately sized work-piece: substantially as described.

4. In a centerless grinding machine, in combination, a grinding wheelrotatable at relatively high speed, a regulating wheel rotatableatrelatively low speed, the grinding wheel moving downwardly and theregulating wheel moving upwardly with respect to an interposedwork-piece, and a work guide comprising a plurality of parallel bladeswith means for individually adjusting the blades to make their end facescontact with the periphery of a work-piece at a plurality of points;substantially as described.

In a centerless grinding machine, in combination, a grinding wheelrotatable at relatively high speed, a regulating wheel rotatable atrelatively low speed, the grinding wheel moving downwardly and theregulating wheel moving upwardly with respect to an interposedwork-piece, a pair of guide blocks having grooves, blades movablymounted in the grooves. means for individually moving said blades, andmeans for clamping said blades with their end faces in contact with awork-piece at a plurality of points; substantially as described.

6. In a grinding machine, a grinding wheel and means for rotatablysupporting a workpiece in contact with said wheel, said meanscomprising. a plurality of parallel blades having their end facesarranged to contact with the periphery of the work-piece at a pluralityof points; substantially as described.

In testimony whereof I hereunto affix my signature.

WILLIAM CHAPMAN.

